The Next Generation Virgo Cluster Survey. IX. Estimating the Efficiency of Galaxy Formation on the Lowest-Mass Scales

TL;DR

This study uses the Virgo cluster survey to estimate the stellar-to-halo-mass ratio for dwarf galaxies, revealing that formation efficiency trends extend to the faintest, least massive galaxies observed.

Contribution

It extends the understanding of galaxy formation efficiency to the lowest-mass dwarf galaxies, showing scale-invariant trends in the stellar-to-halo-mass ratio.

Findings

SHMR trends extend to faintest dwarf galaxies

Formation efficiency scales invariantly across mass ranges

Results reach stellar masses of approximately 10^5 solar masses

Abstract

The Next Generation Virgo Cluster Survey has recently determined the luminosity function of galaxies in the core of the Virgo cluster down to unprecedented magnitude and surface brightness limits. Comparing simulations of cluster formation to the derived central stellar mass function, we attempt to estimate the stellar-to-halo-mass ratio (SHMR) for dwarf galaxies, as it would have been before they fell into the cluster. This approach ignores several details and complications, e.g., the contribution of ongoing star formation to the present-day stellar mass of cluster members, and the effects of adiabatic contraction and/or violent feedback on the subhalo and cluster potentials. The final results are startlingly simple, however; we find that the trends in the SHMR determined previously for bright galaxies appear to extend down in a scale-invariant way to the faintest objects detected in the survey. These results extend measurements of the formation efficiency of field galaxies by two decades in halo mass, or five decades in stellar mass, down to some of the least massive dwarf galaxies known, with stellar masses of $\sim 10^5 M_\odot$.